<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // 修改length长度
        var arr = ['red', 'green', 'yellow', 'brown'];
        console.log(arr.length);
        arr.length = 5;
        console.log(arr);
        console.log(arr[3]);
        console.log(arr[4]);
        // 新增数组元素 修改索引号 追加数组元素
        var arr1 = ['red', 'green', 'yellow'];
        arr1[3] = 'pink';
        console.log(arr1);
        arr1[4] = 'orange';
        console.log(arr1);
        arr1[0] = 'yellow';
        console.log(arr1);
    </script>
</body>

</html>